1. Field
The present invention generally relates to an apparatus and method of controlling electric power supply to a memory in an image processing apparatus, and a recording medium storing electric power supply control program.
2. Background
The recent image processing apparatus such as image forming apparatus operates in a plurality of operation modes such that it may be switched to an energy save mode when it is not in use to reduce electric power consumption. When the operation mode is switched to the energy save mode, various data stored in a dynamic memory such as a dynamic random access memory (DRAM) is transferred to a nonvolatile memory such as a hard disk. The DRAM is then switched to a self refresh mode in which the internal clock is inactivated, thus reducing electric power consumption by the apparatus.
On the other hand, in the recent portable device, electric power supply to a DRAM storing OS data regarding an operating system may be stopped after transferring the OS data to a nonvolatile memory, for example, as described in Japanese Patent Application Publication No. 2004-199339.
This technique of stopping electric power supply to the DRAM may be applied to the image processing apparatus to further reduce electric power consumption when the image processing apparatus is not in use. However, since the OS data in the DRAM is lost, the OS data that is transferred to the nonvolatile memory needs to be deployed onto the DRAM when the operation mode is switched from the energy save mode. This requires a longer time for the image processing apparatus to be operable again such that it would be inconvenient for the user. If the energy save mode is switched to the normal operation mode due to access by another apparatus through a network, a communication error may occur if a response from the image processing apparatus being accessed is slow.